Field of the Disclosure
The present disclosure relates to a digital X-ray detector using a thin film transistor, and more particularly, to an array substrate of an X-ray detector, a digital X-ray detector including the same, a method for manufacturing an array substrate of an X-ray detector, and a method for manufacturing an X-ray detector. Although the present disclosure is suitable for a wide scope of applications, it is particularly suitable for tracking a defective line with high accuracy in the thin film transistor array substrate of the X-ray detector.
Description of the Background
In a diagnostic X-ray examination method currently has been used for medical purposes, an X-ray sensing film is used in taking an X-ray and it takes a predetermined printing time to get a result thereof.
However, with a recent development of semiconductor technology, a digital X-ray detector using a thin film transistor has been researched and developed. The digital X-ray detector uses a thin film transistor as a switching element and thus enables a user to make a diagnosis in real time at the time of irradiating an X-ray.
Generally, the digital X-ray detectors are classified into two types, i.e., a direct type DXD and an indirect type DXD. The direct type DXD includes an amorphous selenium (Se) layer laminated on an upper layer of a thin film transistor array substrate and a transparent electrode formed on the amorphous Se layer, and detects a current as a pixel electrode of the thin film transistor receives a charge from the Se layer and then performs a signal processing. The indirect type DXD includes a scintillator, and if an X-ray is converted into a visible ray by the scintillator, the visible ray is converted into an electrical signal by a PIN diode, and then a series of signal processing is performed.
Meanwhile, in the conventional X-ray detector, a mask used for performing an exposure process to an array substrate is small. Thus, in order to manufacture a large-sized panel, a stitch shot exposure method of performing exposure by shifting the mask on a base substrate several times has been used.
Generally, if a defect, such as open or short, occurs in a signal line, a plurality of lines on an array substrate are patterned together with identifiers for the respective lines in order to find out a defective signal line on the array substrate using a detector.
However, in case of the stitch shot exposure method, an exposure process is performed by shifting the same mask several times. Thus, the same identifier is repeatedly patterned on one base substrate. FIG. 1 is a photograph of an array substrate on which identifiers are formed by a conventional stitch shot exposure method, which will be explained with reference to FIG. 1.
A mask used in FIG. 1 includes the 1st to 256th identifiers. Thus, the 257th line (a line exposed by shifting the mask for the second time in the photograph of FIG. 1) becomes the 1st identifier, which is the same identifier as the 1st line. As such, there are more than one signal lines including the same identifier, and, thus, it is impossible to accurately find out the position of the defective signal line. Accordingly, a solution thereto is needed.